<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <!-- div*10{hello} -->
    <!-- div*10{$} -->
    <!-- div*100{case $:} -->
</body>
<script>
    var grade = Math.round(Math.random() * 100);
    var shi = Math.floor(grade / 10); 
    console.log(grade,shi);

    switch (shi) {
        case 0:
        case 1:
        case 2:
        case 3:
        case 4:
        case 5:
            document.write(grade + "分,不及格");
            break;
        case 6:
            document.write(grade + "分,及格");
            break;
        case 7:
            document.write(grade + "分,一般");
            break;
        case 8:
            document.write(grade + "分,良好");
            break;
        case 9:
            document.write(grade + "分,优秀");
            break;
        case 10:
            document.write(grade + "分,大神,带带我");
            break;
    }

</script>

</html>